<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<script type="text/javascript">
		function A() {
			this.width = 10;
			this.data = [1,2,3];
			this.key = "this is A";
		}
		A._objectNum = 0;
		A.prototype._objectNum1 = 0;
			//定义A的属性
		A.prototype.say = function(){
			//给A的原型对象添加属性
			alert("hello world")
		}

		var refa = new A();
		alert(refa._objectNum1);
		alert(A._objectNum);
		refa.say();

	</script>
</body>
</html>